Ionic Equilibrum

The ionisation constant of the weak acid HF whose concentration is 0.1 M is $3.5 \times 10^{-4}$ The Equilibrium constant value for the reaction $\mathrm{F}^{-}+\mathrm{H}_2 \mathrm{O} \leftrightharpoons \mathrm{HF}+\mathrm{OH}^{-}$is _________ and the pH of aqueous solution of the weak acid is __________ .